Cytology And Cytochemistry Of Hemocytes Of Mytilus-Edulis And Their Responses To Experimentally Injected Carbon Particles

Hemocytes of Mytilus edulis were examined cytologically and cytochemically. On the basis of structure, staining reactions, and phagocytic behavior, they were divided into two main groups: basophilic hemocytes and eosinophilic granular hemocytes (granulocytes). The basophilic cells were further divided into small lymphocytes and larger phagocytic macrophages reactive for lysosomal hydrolases. Mitosis was observed in granulocytes and in small lymphoid cells, believed to be the stem cells for the basophilic cell line. A few cells appeared to be intermediate between lymphocytes and small granulocytes. Macrophages were the main cell type involved in the clearance of injected carbon particles. However, granulocytes did show some phagocytic activity. Brown cells displaying apparent amoebocytic behavior were found to contain Fe3+ and Pb2+ in cytoplasmic inclusions, some of which were also reactive for β-glucuronidase and glucosaminidase. These cells appear to have a separate origin from the hemocytes.

Aspects Of Gametogenesis In The Marine Mussel Mytilus-Edulis-L

Marine bivalve molluscs have in recent years attracted considerable attention for a variety of reasons, not least of which is their importance as a source of food for man. Much of this research has concentrated on studies of reproduction; Mytilus viridis (India: Nagabhushanam & Mane, 1975), M. edulis aoteanus and Aulacomya maoriana (New Zealand: Kennedy, 1977);Choromytilus meridionalis and Aulacomya ater (South Africa: Berry, 1978); Mytilus (= Perna) perna (Brazil: Lunetta, 1969); M. edulis planulatus (Australia: Wilson & Hodgkin, 1967); Mytilus californianus and M. edulis (U.S.A.: Hines, 1979); Mytilus galloprovincialis (France: Lubet, 1959) and M. edulis (U.K.: Chipperfield, 1953; Seed, 1975; Bayne et al. 1978). A review of the literature revealed that in the majority of studies cytology was used as a descriptive tool for the ‘staging’ (Chipperfield, 1953; Lubet, 1957; Seed, 1975, 1976) of the developing gametes and certain anomalies were apparent with regard to the nomenclature of the connective tissue matrix of the mantle lobes.

On the ultrastructure of Gephyrocapsa oceanica (Haptophyta) life stages.

Gephyrocapsa oceanica is a cosmopolitan bloom-forming coccolithophore species belonging to the haptophyte order Isochrysidales and family Noëlaerhabdaceae. Exclusively pelagic, G. oceanica is commonly found in modern oceans and in fossil assemblages. Its sister species Emiliania huxleyi is known to possess a haplo-diplontic life cycle, the non-motile diploid coccolith-bearing cells alternating with haploid cells that are motile and covered by non-mineralized organic scales. Since the cytology and ultrastructure of other members of the Noëlaerhabdaceae has never been reported, it is not clear whether these features are common to the family. Here, we report on the ultrastructure of both the non-motile calcifying stage and the non-calcifying motile stage of G. oceanica. We found no significant ultrastructural differences between E. huxleyi and G. oceanica either in the calcifying diploid stage or the haploid phase. The similarities between these two morphospecies demonstrated a high degree of conservation of cytological features. We discuss the significance of these results in the light of the evolution of the Noelaerhabdaceae.